74 JOAN V. POWELL 



The behavior of inert particles coated with the spore peptide was very similar 

 to that of B. subtilis spores. The technique of "ion spectra" (Dejong, 1949) 

 was also applied to particles coated with the spore peptide and to B. subtilis 

 spores, and further similarities between the two surfaces were indicated. 

 B. megaterium spores gave a cation spectrum which suggested a possibility 

 for their surface composition other than the lipid-protein complex first sug- 

 gested. The cation spectrum obtained with B. megateriurn spores closely 

 resembled that of inert particles coated with a polyglutamic acid preparation 

 isolated from B. anthracis. It is now suggested that the surface layer of 

 the B. megateriurn spore could be composed of the same type of material as 

 appears to be present at the surface of B. subtilis spores, but orientated 

 differently so that more carboxyl groups are presented to the aqueous medium. 



The Mechanism of Release of the DAP-hexosamine Peptide 

 from the Germinating Spore 



Lysozyme accelerated the release of the DAP-hexosamine peptide from 

 spore coat preparations of B. megateriurn (Strange and Dark, 1956). It 

 was suggested that a lysozyme-like lytic system might be responsible for the 

 release of the peptide during germination, and that the activation of this sys- 

 tem might be one of the first stages of the germination process. Evidence in 

 favor of this possibility has recently been obtained. The DAP and hexos- 

 amine content of whole cells of B. cereus was fairly constant during growth 

 and sporulation, but during sporulation there was a change in distribution 

 of DAP and hexosamine between the soluble and insoluble fractions of the 

 disintegrated cell. DAP and hexosamine were found in the insoluble fraction 

 of vegetative cells and in the soluble fraction of sporulating cells and spores. 

 Extracts of sporulating cells and spores contained a lytic system capable of 

 releasing the DAP-hexosamine peptide from the insoluble fraction of vege- 

 tative cells. This lytic system resembled lysozyme in its mode of action and 

 its heat stability (Strange and Dark, 1956). A similar lytic system was 

 present in extracts from spores of an avirulent strain of B. anthracis. The 

 insoluble fraction from spores of B. megateriurn showed moderate activity 

 although none could be demonstrated in the soluble fraction (Strange and 

 Dark. 1956). 



Conclusions 



In contact with certain simple substances, and under conditions which may 

 be totally unsuitable for growth, the resting spore germinates, i.e.. it loses its 

 heat-resisting properties, becomes permeable to stains, and swells slightly. 

 While these changes are occurring calcium dipicolinate is excreted and a non- 

 diaJyzable peptide of characteristic constitution is released from the spore 

 coat. As far as we can judge, these changes take place simultaneously. In 



